Jackson (4-5) gave up four hits and ended his three-start losing streak.

Pomeranz (2-4 for Boston) was an All-Star for the Padres this season and 8-7 in the NL before being traded to the Red Sox in mid-July.

Brandon Maurer worked the ninth for his eighth save in 13 chances. He gave up a one-out single to Hanley Ramirez, then struck out Jackie Bradley Jr. and got pinch hitter David Ortiz on a flyball.

Rosales hit his career-high ninth homer of the season in the fourth, and the San Diego pitchers made it stand up.

Pomeranz gave up two runs and six hits in 5 2/3 innings. He struck out five with a walk.

Chris Young’s pinch-hit homer off reliever Brad Hand to open the eighth cut the Padres’ lead to 2-1.

Aaron Hill followed with a pinch-hit double but was stranded at third when Hand struck out Brock Holt and Xander Bogaerts.

Hanley Ramirez had three hits for Boston.

Boston’s best chance against Jackson came in the seventh. But with two on and none out, he got Bradley to ground into a double play and fanned Yoan Moncada on a full-count offspeed pitch. TRAINER’S ROOM

Red Sox: RHP Koji Uehara (strained pectoral muscle) was activated off the disabled list. He will be available on Tuesday, according to manager John Farrell. Padres: CF Jon Jay (right forearm) will be added to the roster on Tuesday after playing in three minor league games. Jay missed 66 games.